Celine Dion is ready to talk about the death of her late husband, René Angélil.

In her first television interview since Angélil's death in January after a long battle with throat cancer, the 48-year-old singer describes her somber final moments with her husband of 21 years. Dion says she told Angélil not to "worry" anymore, and to "leave in peace."

"'You were worrying for my career. You were worrying for the children. You were worrying for everything. It's enough. Do you trust me?'" Dion says she told Angélil in a new interview with ABC News. "'Please do. Trust me. The kids are fine. I'm fine. I promise you we're gonna be OK. Please leave in peace. I don't want you to worry.'"

Dion also had the difficult task of breaking the news to their children -- 15-year-old René-Charles, and 5-year-old twins Nelson and Eddy. She says she used the 2009 Disney film Up to talk about Angélil's death with her younger boys.

"Before I told them that their dad was not there, I talked about when we -- everybody -- gets sick. Then I said, 'Do you remember the movie Up?'" Dion says. "'Oh,' they said, 'Yes, Ellie went up. You know, she, with the balloons.' And I said, 'Well, yeah … You know, today Papa went up.'"

"The only thing I wanted is for them to say 'up,'" Dion adds about where her sons say their late father went. "Up is a good thing. Up is uplifting."

Dion and her children later released balloons and "pixie dust" into the sky to honor Angélil.

Dion describes more of her intense heartbreak this year in another new interview with People, explaining that she wants to prove to her children that their mother is "strong." She returned to her Las Vegas residency in February, just over a month after Angélil's death. At this Sunday's Billboard Music Awards, she'll be receiving the Icon award and performing.

On Tuesday, she resumes her Caesars Palace residency.

"René always insisted the show must go on," Dion says. "You know what, I'm 48 years old and I lost the love of my life. I miss him a lot from when he was great but not when he was suffering. I cannot be selfish. You have to let people go. I feel at peace."

The "My Heart Will Go On" singer acknowledges the difficult struggle the two faced in dealing with his three bouts with cancer.

"It's been a long, long journey," Dion says. "We were living in hope, knowing that there's no hope. ... I'm not the type of person who's going to say, 'I know he's going to make it.'"

"There were times when I was very, very scared and he'd write me, 'The end is near, I feel it,'" she says about Angélil eventually losing his ability to talk. "I would go back and say, 'How can you say that? Are you in more pain?' Now I know it's possible for someone dying to feel when it comes."

Although she is clearly devastated, Dion stresses that she's glad Angélil is no longer in pain.

"He left me with all of his strength," she says. "Every day we live with him, just not physically. I'm thankful that he does not suffer anymore."